Beth Shapiro skriver om mammut utdöende i den vetenskapliga artikeln: Pattern of extinction of the woolly mammoth in Beringia, (2012) Nature Communications volym 3, http://www.nature.com/ncomms/journal/v3/n6/abs/ncomms1881.html”Remaining continental mammoths, now concentrated in the north, disappeared in the early Holocene with development of extensive peatlands, wet tundra, birch shrubland and coniferous forest. Long sympatry in Siberia suggests that humans may be best seen as a synergistic cofactor in that extirpation. The extinction of island populations occurred at ~4 ka. Mammoth extinction was not due to a single cause, but followed a long trajectory in concert with changes in climate, habitat and human presence.”
Se även: Life and extinction of megafauna in the ice-age Arctic (2015) PNAS vol. 112 no. 46 http://www.pnas.org/content/112/46/14301.full

Handeln med mammutbetar sker både öppet och dolt. Uppskattningen på 60 ton kommer från en nyhetsartikel i National Geographic, den är mycket läsvärd och innehåller fantastiska bilder: Of Mammoths and Men (2013) http://ngm.nationalgeographic.com/2013/04/125-mammoth-tusks/larmer-text”Nearly 90 percent of all mammoth tusks hauled out of Siberia—estimated at more than 60 tons a year, though the actual figure may be higher—end up in China, where legions of the newly rich are entranced by ivory.”

De‐extinction: raising the dead and a number of important questions (mars 2014) Heard Frontiers of Biogeography volym 6
From dinosaurs to dodos: who could and should we de-extinct? (Mars 2014) Jones Frontiers of Biogeography volym 6
De-extinction in a crisis discipline (mars 2014) Donlan Frontiers of Biogeography volym 6
Länk till samtliga: http://www.biogeography.org/html/fb/FBv06i01_All.pdf